MATLAB: Difference in outerjoin in R2015b and R2016a

MATLABtableversion

I have been encountering a difference in the functionality of outerjoin between R2015b and R2016a:
In R2016a, the following code runs as expected:
Table1 = table({'a';'b';'c'},[1;2;3],'VariableNames',{'Key','Value'});
Table2 = Table1([false, false false],:);
joined = outerjoin(Table2,Table1,'Key','Key','MergeKeys',1);
Resulting in joined being a 3×3 table that's like Table1 but with a column full of NaN.
In R2015b, however, I get
Error using table/outerjoin (line 152)
With two inputs, the first argument must be a vector. Use three-input syntax for matrices.
My question is twofold:
  1. What changed between the two versions to account for the difference in behavior?
  2. What can I do to consistently avoid this error?
Related Question